Back to Annual Meeting Posters

Objective: Vein grafts are used for CABG, yet suffer poor long-term patency rates due to intimal hyperplasia (IH) and superimposed atherosclerosis. Stretching of the graft due to arterial pressure leads to IH, which can be reduced with cumbersome external sheaths. Photochemical Tissue Passivation (PTP) is a simple method to crosslink surface collagen by a light activated process, stiffening the grafts and reducing IH without a sheath.
Design: To evaluate the effect of PTP venous elasticity, six porcine jugular veins were divided in half; one segment served as control, the other treated with 0.1% Rose Bengal and a 532 nm laser. 33 small samples were prepared, 16 control and 17 treated. Stress-strain curves were generated for each. Collagenase digestion was performed on four treated and four untreated rat epigastric vein segments to demonstrate collagen crosslinking. In-vivo testing was done by placing an epigastric vein interposition graft in the femoral artery of 16 rats. Half were treated with PTP. Grafts were harvested after 4 weeks.
Setting: Academic center laboratory
Main outcome measures: Intimal thickness after 4 weeks
Results: Modulus of elasticity was 587±288 and 1008±555 KPa for untreated and treated samples (p=0.01). Collagenase digestion was 66±8 and 300±0 min for untreated and treated samples (p<0.001). After four weeks, intimal thickness was 80±56 and 24±22 µm in untreated and treated grafts (p=0.03). Medial thickness was 216±69 and 141±40 µm in treated and untreated grafts (p=0.04). All grafts were patent.
Conclusion: PTP stiffens venous conduits by collagen cross-linking without a cumbersome sheath. This in turn leads to a statistically significant, 70% reduction in intimal hyperplasia of vein grafts after four weeks. PTP could potentially improve long-term outcomes after CABG.